promethium (Pm) /-mē″thē·əm/ [L, Prometheus, mythic character who gave fire to humans] , a radioactive rare earth metallic element. Its atomic number is 61; its atomic mass is 145.
promethium (Pm)
promethium (Pm) /-mē″thē·əm/ [L, Prometheus, mythic character who gave fire to humans] , a radioactive rare earth metallic element. Its atomic number is 61; its atomic mass is 145.